有几种方法取决于您拥有的版本 - 请参阅 关于字符串聚合技术的 Oracle 文档.一个非常常见的方法是使用 LISTAGG代码>:

SELECT pid, LISTAGG(Desc, ' ') WITHIN GROUP (ORDER BY seq) AS 描述从 B 组按 pid；

然后加入 A 以挑选出你想要的 pids.

注意:开箱即用，LISTAGG 仅适用于 VARCHAR2 列.

Would it be possible to construct SQL to concatenate column values from multiple rows?

The following is an example:

Table A

PID
A
B
C

Table B

PID   SEQ    Desc

A     1      Have
A     2      a nice
A     3      day.
B     1      Nice Work.
C     1      Yes
C     2      we can 
C     3      do 
C     4      this work!

Output of the SQL should be -

PID   Desc
A     Have a nice day.
B     Nice Work.
C     Yes we can do this work!

So basically the Desc column for out put table is a concatenation of the SEQ values from Table B?

Any help with the SQL?

There are a few ways depending on what version you have - see the oracle documentation on string aggregation techniques. A very common one is to use LISTAGG:

SELECT pid, LISTAGG(Desc, ' ') WITHIN GROUP (ORDER BY seq) AS description
FROM B GROUP BY pid;

Then join to A to pick out the pids you want.

Note: Out of the box, LISTAGG only works correctly with VARCHAR2 columns.